WATER TREATMENT AND REUSE SYSTEM
System and methods are disclosed for filtering wastewater. In one embodiment, a water filtering system comprises a first filtering stage and a second filtering stage. The first filtering stage receives a flow of wastewater, and uses electrocoagulation to separate suspended particles from the wastewater and produce filtered wastewater. The second filtering stage receives the filtered wastewater from the first filtering stage, and uses mechanical filtering to remove suspended particles from the filtered wastewater and produce filtered water that is substantially free from suspended particles.
This non-provisional application claims priority to U.S. provisional applications 61/185,477, 61/185,504, and 61/185,497, each of which were filed on Jun. 9, 2009. These provisional applications are incorporated by reference as if fully provided herein.
FIELD OF THE INVENTIONThe invention relates to the field of water treatment systems, and more particularly, to systems and methods for filtering wastewater.
BACKGROUNDOil production industries are consistently forced to deal with water challenges that result from drilling processes. During a drilling process, an oil/water mixture is pumped from the ground, which is referred to as production water or wastewater. The wastewater coming from the ground could be 95% water and 5% oil by volume. The wastewater may also include traces of heavy metals and other contaminants. Before the wastewater can be safely disposed of or reused, the contaminants need to be removed. Thus, oil companies have the challenge of removing contaminants and safely disposing of the wastewater. Other companies in other industries face similar problems of having to safely dispose of wastewater.
One common way of treating wastewater is through a reverse osmosis filtering process. Unfortunately, the reverse osmosis filtering process is expensive and can be relatively slow especially when the oil content in the wastewater is high. Another common way of treating the wastewater is through a distillation process. Again, the distillation process is expensive and time consuming. Yet another way of treating the wastewater is through a chemical processes. The chemical processes are again expensive, and further processes are needed to return the wastewater to a safe level.
Thus, there is a need in the art for improved filtering systems so that wastewater can be safely and reliably processed.
SUMMARYEmbodiments described herein provide improved systems for filtering wastewater. The filtering systems include a first filtering stage that uses electrocoagulation (EC) to separate suspended particles from the wastewater. The filtering systems also include a second filtering stage that uses mechanical filtering to remove suspended particles that remain to produce filtered water that is free or substantially free from suspended particles. This multi-stage filtering process effectively filters wastewater in a cost-effective manner while allowing for high through-put levels.
One embodiment comprises a water filtering system comprising a first filtering stage and a second filtering stage. The first filtering stage receives a flow of wastewater, and uses electrocoagulation to separate suspended particles from the wastewater and produce filtered wastewater. The second filtering stage receives the filtered wastewater from the first filtering stage, and uses mechanical filtering to remove suspended particles from the filtered wastewater and produce filtered water that is free or substantially free from suspended particles.
In another embodiment, the water filtering system includes a third filtering stage that receives the filtered water from the second filtering stage, and removes dissolved particles from the filtered water to produce filtered water that is free or substantially free from dissolved particles.
In another embodiment, the water filtering system includes a pre-filtering stage that removes hydrocarbons from the flow of wastewater before the wastewater is fed to the first filtering stage.
Other exemplary embodiments may be described below.
Some embodiments of the present invention are now described, by way of example only, and with reference to the accompanying drawings. The same reference number represents the same element or the same type of element on all drawings.
The figures and the following description illustrate specific exemplary embodiments of the invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the invention and are included within the scope of the invention. Furthermore, any examples described herein are intended to aid in understanding the principles of the invention, and are to be construed as being without limitation to such specifically recited examples and conditions. As a result, the invention is not limited to the specific embodiments or examples described below, but by the claims and their equivalents.
When in operation, first filtering stage 110 receives a flow of wastewater 102. First filtering stage 110 uses electrocoagulation (EC) to separate suspended particles from the wastewater 102 and produce filtered wastewater 104. Second filtering stage 120 receives the filtered wastewater 104 from first filtering stage 110. Second filtering stage 120 uses mechanical filtering (e.g., one or more mechanical filters) to separate out or remove suspended particles from the filtered wastewater 104 that may remain, and produce filtered water 106 that is free or substantially free from suspended particles. The filtered water 106 may still have some suspended particles, but the number of particles (in parts per million) have been reduced to a level that is considered safe for disposal or reuse. This multi-stage filtering process removes polymers, paraffin, heavy metals, or other contaminating particles from the wastewater 102, which results in water that may be disposed of or reused safely.
Although not shown in
When in operation, EC system 412 receives the flow of wastewater 102. As illustrated by the arrows in
The wastewater 102 from EC system 412 is gravity-fed to settling tanks 414-416 where the wastewater 102 is temporarily stored. As the wastewater 102 sits in settling tanks 414-416, the neutralized particles in the wastewater 102 separate from the wastewater 102 and fall to the bottom of settling tanks 414-416. The particles that are released from the wastewater 102 form a slurry of solids on the bottom of settling tanks 414-416, while the filtered water 104 remains as a liquid on top of the slurry.
Settling tanks 414-416 may be filled one at a time. For example, after settling tank 414 has been filled, wastewater 102 from EC system 412 may be fed to settling tank 415 while the wastewater 102 in settling tank 414 is allowed to sit. Similarly, after settling tank 415 has been filled, wastewater 102 from EC system 412 may be fed to settling tank 416 while the wastewater 102 in settling tanks 414-415 is allowed to sit. When settling tank 416 is being filled or about to be filled, the filtered wastewater 104 from settling tank 414 may be fed to second filtered stage 120 so that the liquid in setting tank 414 is emptied. When settling tank 414 is emptied, the filtered wastewater 104 from settling tank 415 may be fed to second filtered stage 120 so that the liquid in setting tank 415 is emptied. Settling tanks 414-416 may be used in this manner to receive wastewater 102 from EC system 412 and feed filtered wastewater 104 to second filtering stage 120.
In another embodiment, settling tanks 414-416 may be connected in series so that filtered wastewater 104 from settling tank 414 may be fed to settling tank 415 where particles may be allowed to further separate from the wastewater 102. Filtered wastewater 104 from settling tank 415 may be fed to settling tank 416 where particles may again be allowed to further separate from the wastewater 102. The filtered wastewater 104 from settling tank 416 may then be fed to second filtered stage 120.
The filtered wastewater 104 sitting in one or more of settling tanks 414-416 is subsequently fed to second filtering stage 120. Second filtering stage 120 includes one or more mechanical filters 422. For example, mechanical filters 422 may comprise multiple filters having a desired pore size for the particles to be filtered, such as a 0.5 micron pore size, a 0.1 micron pore size, etc. Alternatively, mechanical filters 422 may comprise step-down filters where each successive filter in series has a smaller pore size. Within second filtering stage 120, the filtered wastewater 104 is passed through mechanical filters 422 and produces filtered water 106 that is free or substantially free from suspended particles. The filtered water 106 may still have some suspended particles, but the number of particles (in parts per million) have been reduced to a level that is considered safe for reuse or disposal.
When in operation, the wastewater 102 is first passed through pre-filtering stage 340. Thus, the flow of wastewater 102 enters oil separator 542 where oil separator 542 operates to remove oil and other hydrocarbons from the wastewater 102. The wastewater 102 is then passed through one or more Mycelex filters 544, which acts to remove remaining hydrocarbons from the wastewater 102 that was not removed by oil separator 542. The flow of wastewater 102′ that leaves pre-filtering stage 340 should thus be free or substantially free of oil and other hydrocarbons.
The flow of wastewater 102′ then enters first filtering stage 110 where EC system 412 receives the flow of wastewater 102′. As the wastewater 102′ flows up through EC system 412 and out its top, EC system 412 neutralizes the charges of the particles in the wastewater 102′ through electrolysis. The wastewater 102′ from EC system 412 is gravity-fed to settling tanks 414-416 where the wastewater 102′ is temporarily stored. As the wastewater 102′ sits in settling tanks 414-416, the neutralized particles in the wastewater 102′ separate from the wastewater 102′ and fall to the bottom of settling tanks 414-416. The particles that are released from the wastewater form a slurry on the bottom of settling tanks 414-416, while the filtered water 104 remains on top of the slurry.
The filtered wastewater 104 sitting in settling tanks 414-416 is subsequently fed to second filtering stage 120. Within second filtering stage 120, the filtered wastewater 104 is passed through one or more mechanical filters 422. In this example, the filtered wastewater 104 is passed through mechanical filters 422 having a 0.1 micron pore size. Mechanical filters 422 remove particles that are still suspended within the filtered wastewater 104 to produce filtered water 106 that is free or substantially free from suspended particles.
The filtered water 106 from second filtering stage 120 is subsequently fed to third filtering stage 230. Within third filtering stage 230, the filtered water 106 is passed through reverse osmosis filter 532. Reverse osmosis filter 532 acts to remove particles that are dissolved in the filtered water 106 and produce filtered water 508 that is free or substantially free from dissolved particles. For example, reverse osmosis filter 532 may remove sodium, chlorides, or other particles that are dissolved in the filtered water 106. The filtered water 508, at this point, should be considered safe for disposal or reuse.
The slurry that forms on the bottom of settling tanks 414-416 is also processed by water filtering system 500 in the following way. As is illustrated in
Water filtering system 500 as described above advantageously produces clean water (filtered water 508) that may be disposed of safely by simply dumping it onto the ground or into a water system, such as a pond. The filtered water 508 may also be reused in some manner because most or all of the contaminants in the water have been removed. Not only is water filtering system 500 effective in removing contaminants, it can reach through-puts of 1000 gallons per minute, 2000 gallons per minute, or more which allows system 500 to filter large quantities of wastewater. Also, the cost of filtering the wastewater using system 500 is lower than other filtering methods.
In addition to the systems above, embodiments herein may be described as methods of filtering wastewater.
In step 602, an electrocoagulation (EC) process is performed on a flow of wastewater to separate suspended particles from the wastewater to produce filtered wastewater. The EC process may include passing the wastewater through an EC system to neutralize the charges of the particles in the wastewater. The EC process may further include feeding (such as by using gravity) the wastewater from the EC system to one or more settling tanks where the wastewater is temporarily stored. As the wastewater sits in the settling tanks, the neutralized particles in the wastewater separate from the wastewater and fall to the bottom of the settling tanks The particles that are released from the wastewater form a slurry on the bottom of the settling tanks, while the filtered wastewater remains on top of the slurry.
In step 604, the filtered wastewater from step 602 is passed through one or more mechanical filters to separate out or remove suspended particles from the filtered wastewater and produce filtered water that is free or substantially free from suspended particles. The mechanical filters may have any desired pore size, such as 0.1 microns.
Step 606 is an optional step that may be performed on the filtered water produced in step 604. Step 606 comprises passing the filtered water through a reverse osmosis filter or another type of filter to remove dissolved particles from the filtered water and produce filtered water that is free or substantially free from dissolved particles.
Although not specifically spelled out, additional details of the methods of filtering wastewater may be gleaned from the description above regarding the filtering systems.
Although specific embodiments were described herein, the scope of the invention is not limited to those specific embodiments. The scope of the invention is defined by the following claims and any equivalents thereof
Claims
1. A water filtering system, comprising:
- a first filtering stage that receives a flow of wastewater, and uses electrocoagulation to separate suspended particles from the wastewater and produce filtered wastewater; and
- a second filtering stage that receives the filtered wastewater from the first filtering stage, and uses mechanical filtering to remove suspended particles from the filtered wastewater and produce filtered water that is substantially free from suspended particles.
2. The water filtering system of claim 1 wherein the first filtering stage includes:
- an electrocoagulation system that receives the flow of wastewater, and neutralizes charges on the suspended particles in the wastewater; and
- at least one settling tank connected to the electrocoagulation system, where the at least one settling tank receives the wastewater from the electrocoagulation system, and temporarily stores the wastewater to allow the suspended particles having the neutralized charges to separate from the wastewater.
3. The water filtering system of claim 2 wherein the wastewater is gravity-fed from the electrocoagulation system to the at least one settling tank.
4. The water filtering system of claim 1 further comprising:
- a third filtering stage that receives the filtered water from the second filtering stage, and removes dissolved particles from the filtered water to produce filtered water that is substantially free from dissolved particles.
5. The water filtering system of claim 4 wherein:
- the third filtering stage uses reverse osmosis to remove the dissolved particles from the filtered water.
6. The water filtering system of claim 1 further comprising:
- a pre-filtering stage that removes hydrocarbons from the flow of wastewater before the wastewater is fed to the first filtering stage.
7. The water filtering system of claim 6 wherein:
- the pre-filtering stage includes an oil separator and at least one Mycelex filter.
8. The water filtering system of claim 1 further comprising:
- a filter press connected to the at least one settling tank;
- wherein the filter press receives a slurry from the bottom of the at least one settling tank, and separates the slurry into a solid and a liquid,
- wherein the liquid removed from the slurry is fed back to the first filtering stage.
9. A method of filtering wastewater, the method comprising:
- performing an electrocoagulation process on a flow of wastewater to separate suspended particles from the wastewater to produce filtered wastewater; and
- passing the filtered wastewater through at least one mechanical filter to remove suspended particles from the filtered wastewater and produce filtered water that is substantially free from suspended particles.
10. The method of claim 9 wherein performing an electrocoagulation process comprises:
- passing the wastewater through an electrocoagulation system to neutralize the charges of the suspended particles in the wastewater;
- feeding the wastewater from the electrocoagulation system to at least one settling tank where the wastewater is temporarily stored; and
- allowing the neutralized particles in the wastewater to separate from the wastewater and fall to the bottom of the at least one settling tank.
11. The method of claim 9 further comprising:
- passing the filtered water through another filter to remove dissolved particles from the filtered water and produce filtered water that is substantially free from dissolved particles.
12. The method of claim 11 wherein passing the filtered water through another filter comprises:
- passing the filtered water through a reverse osmosis filter.
13. The method of claim 9 further comprising:
- performing an oil separation process on the flow of wastewater to remove hydrocarbons from the wastewater before performing the electrocoagulation process.
14. The method of claim 13 wherein performing an oil separation process comprises:
- passing the wastewater through an oil separator; and
- passing the wastewater through at least one Mycelex filter.
15. A water filtering system, comprising:
- an electrocoagulation system that receives the flow of wastewater, and neutralizes charges on particles that are suspended in the wastewater;
- at least one settling tank connected to the electrocoagulation system, where the at least one settling tank receives the wastewater from the electrocoagulation system, and temporarily stores the wastewater to allow the suspended particles having the neutralized charges to separate from the wastewater; and
- at least one mechanical filter that receives the filtered wastewater from the at least one settling tank, and removes suspended particles from the filtered wastewater to produce filtered water that is substantially free from suspended particles.
16. The water filtering system of claim 15 wherein the wastewater is gravity-fed from the electrocoagulation system to the at least one settling tank.
17. The water filtering system of claim 15 further comprising:
- a reverse osmosis filter connected to the at least one mechanical filter that removes dissolved particles from the filtered water to produce filtered water that is substantially free from dissolved particles.
18. The water filtering system of claim 15 further comprising:
- a pre-filter connected to the electrocoagulation system, where the pre-filter removes hydrocarbons from the flow of wastewater before the wastewater is fed to the electrocoagulation system.
19. The water filtering system of claim 18 wherein the pre-filter includes:
- an oil separator; and
- at least one Mycelex filter.
20. The water filtering system of claim 15 further comprising:
- a filter press connected to the at least one settling tank;
- wherein the filter press receives a slurry from the bottom of the at least one settling tank, and separates the slurry into a solid and a liquid,
- wherein the liquid removed from the slurry is fed back to the electrocoagulation system.
Type: Application
Filed: Jun 8, 2010
Publication Date: Dec 9, 2010
Patent Grant number: 8906237
Inventor: Curt Johnson (Casper, WY)
Application Number: 12/796,523
International Classification: C02F 9/06 (20060101); C02F 1/463 (20060101); C02F 1/44 (20060101);